the tss isnt needed for tcc control.

if its only there for diagnostics that makes it rather useless to me and makes life much easier.

the OSS is used to reverse calculate vehicle speed which is what the ecu uses for shift scheduling , it can be substituted with the vehicle speed sensor no problem.

Do you know any mechanical specifics on the coasting clutch solenoid? AFAIK it locks something to the case to give you engine braking? Do you know when you can and cant have it functional?

And lastly, it was my understanding before a downshift is commanded to 2nd another step is involved, such as commanding 4th for a second then 2nd? Do you know any details on that?

Thanks Mark

 

or anyone?

I found some info digging in to it more

MCM3 is the catch code for those motor home ecus, coincidentally ive done some extensively disassembly on that MAAG4 strategy back around 2011 and I know for a fact it has the same algorithms all other 4R100 ecus do. I dont have a valid MCM3 binary to check out but looking through my partial im fairly confident the tss and oss switches are simply disabled and calibrated out.

 

The PCM has a closed loop control system that uses input from the engine speed and the TSS to control lockup. It isn't just used for diagnostics.

Similar to TCC control, the TSS and OSS are used to do a closed loop control on each shift. They are both also used for diagnostics.

I know all about it, like I know the rest of the trans. I did this for a living for 19 years at Ford.

The coast clutch is applied to lock the overdrive one way clutch. This provides engine braking in first, second and third gears. The overdrive one way clutch is bypassed by the overdrive clutch in fourth gear. The coast clutch can be applied anytime except in fourth gear. That would cause a tie up.

It doesn't happen. What may be happening is that whatever you're using to see that is misreading the states of the solenoids during the shift.

 

[QUOTE=Robv27;15599404]Ok guys!! im glad we are all it the same page!! Im feeling good because I have a good update to everyone!
Called Ford Tech Support this Morning again and luckly or I call Blessedly I talked to the same Tech Karl, who is an awesome person, so i told them I had found that the PCM in the RV that did not match the VIN number on my RV. So i gave him the part number of this PCM and he checked and confirmed that was the problem... this PCM calls for the TSS and OSS sensors. So i than gave him my Black cover box PCM number and he said it was the right one, and he even said i had an updated part # there because my RV could use also a TCM # XC3F-CFC but this was superseded to the one I'm supposed to have which is XC3Z-CFD. I asked him if the right PCM was to have the sensors, and he confirmed me that the right PCM for my RV does not read the transmission's data through the TSS and OSS and it doesn't use them. that's why they aren't there!!!!!The trans in fact it gets signal from ABS, VSS(Pumpkin), Trans control switch, MAF sensor, IAT sensor, transmission fluid sensor,Tach (RPM), and throttle position!!! Smart hummm, but scary relying in all these sensors and electronics!! But anyways, I'm extremely relieved and although i feel i got ripped of in this sale, God has a plan! and im still happy cause i paid about 30% of what its worth, and it will be running good soon, and i saved an RV from going to the scrapper...lol
Went to Ford local dealer, and the parts guy said they cant get these PCMs anymore. so i search the net this morning and found a used one with lifetime warranty and checked at this Flagship one Inc. that had great reviews and that fixes electronics and these PCMs. So talked to Craig (great guy btw too) and he also confirmed this 2 are the ONLY 2 PCMs that will work on my RV. not cheap! $379 bucks but its all good!! Im a Happy Camper now, and it should be here sometime next week, I'll slap it on, drive it and ill let you guys know how good it runs!!! Again, Thanks everyone for all the help around here!!, and remember like me... humbly I say this; theres always room to learn!

did this fix the problem? I have the same motor home with the same problem.